The present invention relates to power semiconductor devices and more particularly to III-nitride power semiconductor devices.
A high electron mobility transistor (HEMT) is an example of a conventional power semiconductor device. A HEMT may be formed using a III-nitride-based semiconductor die. Specifically, a HEMT according to the conventionally known art includes a first III-nitride semiconductor body, which may be composed of, for example, undoped GaN, and a second III-Nitride semiconductor body, which may be composed of, for example, AlGaN, disposed over first III-nitride semiconductor body. As is well known, the heterojunction of first III-nitride semiconductor body and second III-nitride semiconductor body results in the formation of a conductive region usually referred to as a two•dimensional electron gas (2DEG).
A typical HEMT further includes at least two power electrodes. The current is conducted through the 2DEG between the two power electrodes.
A HEMT may also include a gate structure which can be operated to disable and enable the 2DEG as desired, thereby turning the device ON or OFF. As a result, a HEMT can be operated like a field effect transistor. Indeed, such a device is generally referred to as a heterojunction field effect transistor (HFET).
Due to their low loss, high current carrying and high breakdown voltage capabilities III-nitride-based heterojunction power semiconductor devices are suitable for power applications. In many such power applications, it is desirable to know the state of the current that is being transmitted through the device. For example, in bridge applications it may be desirable to know the state of current that is being carried in one switch before the other switch in the bridge is turned on in order to, for example, avoid shoot through or other undesirable results. Also, it may be desirable to know the state of the current to ensure that the device is not carrying current beyond its rating to avoid failure or undue power dissipation.